The physical properties, chemical and mineralogical compositions and microscopic structures of diatomites collected from Ankara-Kizilcahamam and Cankiri-Cerkes regions were examined in this study. The diatomites were found to be pure, amorphous, usually soft and easily friable with particle size of 5-50 μm. It was determined that the diatomites were highly with a high water absorption capacity and contained plagioclase, smectite, and quartz minerals. The specific gravity was less than 2.0 g/cm3. A comparison of the diatomites with relevant standards and other reported literature indicated that they can be used as filtration material, pozzolan and insulation material in various industrial fields.